1. Field of the Invention
The invention relates to a pumping device for pumping oil from a storage container to a transmission of a motor vehicle having an oil pump that can be driven optionally by a mechanical direct drive or by a switchable electric drive.
2. Related Art
Pumping devices of this type are used, in particular, in motor vehicles having a hybrid drive. In hybrid drives of this type, the oil pump for supplying a transmission is driven directly by the transmission. If the transmission is at a standstill, its function is to be maintained and the oil pump is therefore to remain in operation.
DE 103 29 215 A1 has disclosed a drive apparatus for a transmission oil pump, in which a single oil pump is driven optionally electrically or directly via a summing transmission. For this purpose, the summing transmission has two powertrains, it being possible for one powertrain to be driven by an internal combustion engine and for the other powertrain to be driven by an electric motor. The summing transmission is designed, for example, as a planetary gear mechanism. The advantage or this design consists in that only a single oil pump has to be used, in order to drive the oil pump optionally electrically or directly. However, the summing transmission leads to a high structural complexity.